The International Monetary Fund is worried. Despite the recovery in the global economy since the financial crisis came to a head two years ago this week, the mood-music in Washington is sombre.

Growth has actually picked up from last year's contraction – which was the first global decline in output since 1945 – reasonably strongly, but everywhere the IMF looks it sees potential problems. It is fearful of a currency war breaking out, concerned that the structural imbalances that caused the crisis have not been tackled, anxious that the spurt in activity in the first half of 2010 was as good as it gets.

The fund's half-yearly World Economic Outlook (WEO) is not forecasting a double dip recession, but clearly the organisation set up 66 years ago to oversee the running of the global economy is not going to be caught with its pants down a second time. Should the dreaded double dip actually materialise, nobody will be able to say that the fund failed to provide sufficient warning.

Some analysts think the fund is being too gloomy. Interest rates are low, budget deficits have exploded to boost demand, governments are preparing to switch on their moneymaking machines for a second time. The corporate sector, after mothballing investment, slashing jobs and squeezing wages, has plenty of cash to invest. And, despite the well-documented travails of the banks, the financial system survived the near-meltdown of 2008, if only just. So what's the panic?

The trouble, as the fund sees it, is twofold. Firstly, in the advanced countries of the west, the private sector appears too weak to take up the baton from the state as public spending is cut and taxes raised to bring down sky-high deficits. Companies have money in the bank but will be reluctant to spend it unless consumer demand is sufficiently strong.

In theory, the way out for these countries is to export more. But here's where the second problem kicks in, because those countries running big current-account surpluses – primarily China, Germany, Japan and the oil producing nations – are reluctant to run them down by importing more.

The imbalances in the global economy were a major cause of the crisis and highlight a weakness in global economic governance that has been apparent since the fund was set up in 1944: pressure can be brought to bear on countries running trade deficits, but not on those running trade surpluses.

In today's WEO, the fund makes the entirely valid point that it would be better for the global economy were countries like China to allow their currencies to appreciate rather than building up massive war chests of reserves. There is, though, nothing that the fund, or the US treasury, can do to force Beijing's hand.

The danger is clear. In the years leading up to the crisis, there were signs of a shift of economic power from west to east. That process has been accelerated by the crisis, with the IMF expecting emerging economies to grow by 7.1% this year and 6.4% in 2011, while the comparative figures for the advanced world are 2.7% and 2.2%.

One concern of the fund is that fresh weakness in the big economies of the west will have knock-on effects on the larger emerging economies. A second is that the international cooperation that marked the early days of the crisis will be abandoned in favour of currency wars and the erection of trade barriers. As things stand, both fears are justified.